Simplify the following expression: $x = \dfrac{1}{3k} + \dfrac{1}{4k}$
In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $3k$ and $4k$ $\lcm(3k, 4k) = 12k$ $ x = \dfrac{4}{4} \cdot \dfrac{1}{3k} + \dfrac{3}{3} \cdot \dfrac{1}{4k} $ $x = \dfrac{4}{12k} + \dfrac{3}{12k}$ $x = \dfrac{4 +3}{12k}$ $x = \dfrac{7}{12k}$